Biocompatibility and Antifungal Effects of Chitosan Nanoparticles Loaded With Nystatin and Carvacrol Against Candida albicans.

BACKGROUND: Nanocarrier-based drug delivery systems enable the co-administration of antifungal agents, enhancing pharmacological efficacy and creating synergistic effects. This study aimed to evaluate the biocompatibility and antifungal properties of chitosan nanoparticles co-loaded with nystatin and carvacrol against Candida albicans. METHODS: Chitosan nanoparticles were synthesized and loaded with nystatin and carvacrol. Their antifungal activity was evaluated by determining the minimum inhibitory concentration (MIC) and checkerboard synergy assays, while antibiofilm activity was measured using a microtiter plate crystal violet assay. Biocompatibility was assessed through hemolysis testing of human red blood cells (HRBCs) and MTT cytotoxicity assays on human foreskin fibroblasts (HFF). RESULTS: The nanoparticles exhibited an average hydrodynamic diameter of 70 ± 1.2 nm with favorable polydispersity (0.21 ± 0.03). The MIC of co-loaded nanoparticles was significantly lower than that of single-drug loaded nanoparticles, and checkerboard assays confirmed strong synergy (FICI 0.16-0.5). Sub-MIC concentrations markedly reduced biofilm formation. At 1000 μg/mL, drug-loaded nanoparticles induced < 5% hemolysis, compared with 15.7% ± 2.7% for blank chitosan nanoparticles. HFF cell viability exceeded 90% across concentrations up to 1000 μg/mL at 24-72 h. CONCLUSION: Co-loading nystatin and carvacrol into chitosan nanoparticles yielded a synergistic antifungal and antibiofilm effect against C. albicans, coupled with excellent hemocompatibility and minimal cytotoxicity, highlighting its potential as a topical therapeutic for oral candidiasis particularly where resistance to azoles is rising. Further in vivo studies are warranted.